The invention relates to valves, especially though not exclusively gas divertor valves applicable to waste heat recovery or other boilers for the purpose of diverting the hot gas stream either through or over the boiler tubes or through a gas by-pass.
Such valves are known but suffer from the drawback of involving relatively complicated construction, especially involving the use of cylindrical sleeve-shaped valve members having a multiplicity of apertures, which present considerable resistance to the flow of hot gas through the valve. Also, known valves do not provide optimum flow paths for the gas stream but cause sudden and severe changes in the direction of gas flow and eddying, which further reduces the efficiency of the valve. The valve is particularly applicable to waste heat recovery from heat engines such as diesel engines, where resistance to gas flow through the valve must be minimised in order to minimise loss of power from the heat engine.
Known valves tend to be such as to accumulate deposits where the gas stream, such as the exhaust gas stream from a diesel engine, contains carbon and other solid particles.
The present invention provides a valve which reduces or eliminates the drawbacks associated with known valves of that kind.